great book on Man he 'appeals to the experience of all countries and ages, that if a people has power, and attempts wrongdoing against another, it also does not omit to conceive the other as very worthless and incompetent, and to repeat this conviction often and emphatically' (Der Mensch, ii. 235). It is easy for us to dot the i and cross the t here; less easy perhaps to realize that what troubled von Baer was the persistence of British and American ethnologists in the polygenist heresy, which he traced (and rightly) to their reluctance to treat their 'black brother' as if he were their relative at all. Judgement in that ethnological controversy went by default, with the victory of the North in the American Civil War; and in 1871 the lion lay down with the lamb, even in London; inveterate foes in the Ethnological Society and the Anthropological merging their fate in one Anthropological Institute. In 1915 the reluctance of the 'tall fair people who come from the north'—I borrow a phrase from Professor Ridgeway—to fraternize with mere brunettes, beyond Rhine and Danube, comes in its turn before the same tribunal as polygenism in 1862.

Our subject, 'Unity in Prehistoric Times', embraces three main topics: (1) the unity of human effort and reason everywhere in Man's struggle with Nature and with his Fellow-man; (2) the special conditions which favoured or hindered unity of prehistoric culture in what has been called elsewhere the 'north-west quadrant' of the Old-World land-mass west of Ararat and the Median hills and north of Sahara, the cradle and nursery of the modern 'western world'; and (3) the convergent lines of advancement within that region, which can be traced through the centuries before Roman policy let Greek culture penetrate almost as deep into peninsular Europe as Alexander's conquests had opened to it the inlands of the Near East.

When we speak of unity in human affairs, and particularly just now, when the supreme unity seems to some to be nationalism, and to others the negation, or rather the supersession of nationalism, we mean the rather complex outcome of several distinct things. This complexity was confessed, unwittingly perhaps, in the first humanist creed: 'I believe in one Blood, one Speech, one Cult, one congruous Way of Living.'[2] Modern ethnology, indeed, tends to subsume cult under way-of-living, as a peculiarly delicate test of conformity—and to regard language, alongside of both cult and way-of-living, as another manifestation of the same human reason; distinguishing therefore two kinds of unity—one physical or morphological, as of one animal species in an animal kingdom, the other cultural or psychological, as of the sole incarnate occupant of a realm of mind; and classifying the 'Science of Man' accordingly. But, in essentials, that Athenian creed will serve: our latest ethnologists, and statesmen too, are faced with the same league of problems.

THE UNITY OF MANKIND AS AN ANIMAL SPECIES

Whatever Greek statesmen thought about the gulf between Greek and Persian, or Greek and Barbarian generally, Greek ethnologists raised no fundamental barrier between the different sorts of Man. Good naturalists as they were, and experienced breeders of farm-stock, they accepted white, brown, and black men; and were prepared to accept any other breed that Nearchus or Pytheas might confront them with, as members of one brotherhood, just as they accepted white, brown, or black sheep, with horns of Ammon or with none. Eratosthenes, most philosophical, and therewith most political of them all, was bred in Cyrene, where some Greeks seem to have been black; and he worked in Alexandria, where the University was a human Zoo like that of London or Berlin. Their simple farmer's theory of natural selection attributed 'scorched-faced' Aethiopians to sunburn, and other racial types to large factors of region and régime. The classical treatise is that of Hippocrates 'On Air, Water, and Places'.[3]

In the modern world, too, no serious doubt was cast on the specific unity of mankind, handed down from antiquity, until Linnaeus and Buffon had refined upon the biological notions of genus and species (for both of which there is only one word in Greek), and had defined species by the criterion of fertility. Now not only the great explorers, but every ship's captain, knew by this time that white men, at all events, would form fertile unions with all known kinds of humanity. But in the eighteenth century it became known also, and in the same empirical way, that the fertility of unions between white men and black was imperfect; and as this was the only human cross for which there was any large quantity of evidence, the impression grew that the zoological distance between these races was greater than had been supposed. On the other hand, eighteenth-century formulators of the 'Rights of Man' challenged reconsideration of the current practice of negro slavery; and the upshot was a controversy. Abolitionists contended that the 'black brother' was indeed a blood brother, and entitled to the 'Rights of Man'; their opponents replied that the negro, being (as they held) of another species, might justly be treated in all respects as one of white man's domestic animals, and be his property as well as his drudge. At the turn of the century, the adherence of Cuvier gave prestige to Polygenesis on its scientific side: and it took all the reasonableness of Prichard in the next generation to turn the tide even in England. But the issue of the American Civil War, to which reference has already been made, coincided so closely in time with the work of Darwin and Lyell on the real meaning of species and on the antiquity of man, that the controversy was closed without bitterness. The new phase of Polygenism which seems now to be opening, with successive discoveries of the quaternary stratification of races, and Keith's analysis of the family tree of the Hominidae, starts from wholly different data, unembarrassed by fears or hopes of a 'Neanderthal' origin for the Negro, or for any living or recent Homo.

The 'human family' then seems re-established as something more than a platform phrase; and separatists (who are always with us) have had to fall back upon another criterion of disunity.

THE UNITY OF MANKIND AS A RATIONAL ANIMAL

Omitting language for a moment (which since first telling of the 'Tower of Babel' story has somewhat fallen from grace as a symptom of unity among mankind), or rather, subsuming it as one of the most essential exhibitions of rationality, and indeed its chief instrument, we come to Man's unity as a creature possessed of reason, and expressing this reasoning habit in specific modes of living, under whatever external surroundings. These being almost infinitely various, it is not always easy to compare examples of Man's reaction to them. For proof of the uniformity of human reasoning, indeed, we have to begin almost from an animal plane. 'Hath not a Jew eyes? Hath not a Jew hands, organs, dimensions, senses, affections, passions? Fed with the same food, subject to the same diseases, healed by the same means, warmed and cooled by the same summer and winter, as a Christian is?' And not only is men's hunger, and their sensitiveness to 'the same summer and winter' similar: their ways of satisfying hunger, their conduct of the food-quest, their elementary organizations 'for the sake of maintaining life', as Aristotle expressed it, exhibit one mental type throughout. In the domestication of nature's gifts it is the same: in the fashioning of implements and weapons, the improvisation of clothing and shelter, the almost